Method of making a plate-type heat exchange unit

ABSTRACT

A pair of like flat rectangular steel sheets are superposed face-to-face and seam-welded together marginally, as well as being further united rigidly between margins by a pattern of elongated seam weld and interrupted seam or spot weld-type unions. The latter are arranged in longitudinally extending rows paralleling horizontal and intermediate seam welds, the interrupted welds of successive rows being in a longitudinally and laterally staggered relationship defining a symmetric pattern of uniformly diamond-shaped areas between sets of four of the interrupted welds. Either before or after the sheets are weldunited in this fashion, they are punched to afford a pair of registering rectangular notches which are optionally located, depending upon the ultimate configuration of the product, at spaces at which a pair of special inlet and outlet pad subassemblies for the heat transfer fluid are to be applied. Each of these units consists of a nipple-like cylindrical pipe length about the circumference of which a pair of like stamped sheet metal pad-like plates are welded. Flat portions of these plates are in turn telescoped in parallel relation to and over a portion of the notched margin of the prior-welded heat transfer plate or sheet sub-assembly, spanning the respective notches, and are thereafter welded leak-tight to said plates about the margins of the two fitting pad components. The full welded assembly is then clamped rigidly along outer margins in an expansion fixture, whereupon hydraulic pressure is applied to the inlet pad fitting (the other being plugged), thus to controllably inflat interior spaces not held by weldments, thus in turn to produce a multiplicity of identical and symmetrically distributed, staggered diamond-shaped pillow-like sub-volumes, as defined by the weld patterning described above; through these spaces a heat transfer fluid medium travels in a well distributed but generally serpentine, parallel flow path from inlet to outlet.

United States Patent [191 Stowell METHOD OF MAKING A PLATE-TYPE [73]Assignee: Tranter Manufacturing, Inc.,

Lansing, Mich.

[22] Filed: Apr. 24, 1974 [21] Appl. No: 463,682

Related US. Application Data [62] Division of Ser. No. 297,892, Oct. 16,1972, Pat. No.

[52] [1.8. Cl 113/118 D; 29/1573 V; 113/118 V [51] Int. Cl. B21D 53/02;B231 15/26 [58] Field of Search 165/170; 62/523; 29/1573 V; 113/118 V,118 D; 29/1573 D [56] References Cited UNlTED STATES PATENTS 2,626,1301/1953 Raskin 62/523 X 2,848,200 8/1958 Jacobs 165/170 X 2,900,1758/1959 McGuffey 165/170 2,974,498 3/1961 Ehrenfreund 62/523 X 3,458,9178/1969 Mueller 29/1573 V R19;778 12/1935 Litle 113/118 V PrimaryExaminer-Lowell A. Larson Assistant Examiner-D. C. Reiley, lll

Attorney, Agent, or Firm-Whittemore, Hulbert & Belknap [57] ABSTRACT Apair of like flat rectangular steel sheets are superposed face-to-faceand seam-welded together marginally, as well as being further unitedrigidly between [111 3,911,843 [4 1 Oct. 14, 1975 margins by a patternof elongated seam weld and interrupted seam or spot weld-type unions.The latter are arranged in longitudinally extending rows parallelinghorizontal and intermediate seam welds, the interrupted welds ofsuccessive rows being in a longitudinally and laterally staggeredrelationship defining a symmetric pattern of uniformly diamond-shapedareas between sets of four of the interrupted welds. Either before orafter the sheets are weld-united in this fashion, they are punched toafford a pair of registering rectangular notches which are optionallylocated, depending upon the ultimate configuration of the product, atspaces at which a pair of special inlet and outlet pad sub-assembliesfor the heat transfer fluid are to be applied. Each of these unitsconsists of a nipple-like cylindrical pipe length about thecircumference of which a pair of like stamped sheet metal pad-likeplates are welded. Flat portions of these plates are in turn telescopedin parallel relation to and over a portion of the notched margin of theprior-welded heat transfer plate or sheet sub-assembly, spanning therespective notches, and are thereafter welded leak-tight to said platesabout the margins of the two fitting pad components. The full weldedassembly is then clamped rigidly along outer margins in an expansionfixture, whereupon hydraulic pressure is applied to the inlet padfitting (the other being plugged), thus to controllably inflat interiorspaces not held by weldments, thus in turn to produce a multiplicity ofidentical and symmetrically distributed, staggered diamondshapedpillow-like sub-volumes, as defined by the weld patterning describedabove; through these spaces a heat transfer fluid medium travels in awell distributed but generally serpentine, parallel flow path from inletto outlet.

2 Claims, 6 Drawing Figures [IIII Lzgo ol lzoooo U.S. Patent 00:. 14,1975 FIG.6

METHOD OF MAKING A PLATE-TYPE HEAT EXCHANGE UNIT This is a division ofapplication Ser. No. 297,892, filed Oct. 16, 1972, now U.S. Pat. No.3,822,742, issued .luly 9, 1974.

CROSS-REFERENCE TO RELATED APPLICATIONS My copending application Ser.No. 346,294, filed Apr. 3, 1973, discloses improved equipment by whichthe herein claimed method of producing the abovedescribed heatingtransfer unit is carried out, as well as procedural operations of a moremechanical nature which are involved in the functioning of thatequipment.

BACKGROUND OF THE INVENTION 1. Field of the Invention The heat transferunit, handling steam or other fluid as a transfer medium, findsapplication in many heat transfer uses, as in chemical processing,metalworking, paper and textile plants, and the like. A typical furtherapplication, as a heat exchange unit for transformer cooling oil, is asa less costly substitute for units as illustrated and described in thepatent to McGuffey, U.S. Pat. No. 2,900,172, of Aug. 18, 1959 of commonownership. Another unit of similar function is the subject matter ofMcGuffey, U.S. Pat. No. 3,502,142, dated Mar. 24, 1970, also of commonownership.

2. Description of the Prior Art The most pertinent prior art patents ofwhich I am aware are Mueller U.S. Pat. No. 3,458,917 of Aug. 5, 1969,and Muffley, U.S. Pat. No. 1,709,865 of Apr. 23, 1929. These relate inthe most general way only to the product and method of the presentinvention.

SUMMARY OF THE INVENTION The invention affords a transfer unit which, asconstituted in the manner described in the Abstract, may be marketed ina limited number of basic styles, each variable in respect to specificdesign, for example, as to the orientation on the expanded heat transfersheet or plate sub-assembly of the two intake and outlet fitting pads,as well as in regard to the material and dimensioning of the structureas a whole to meet a wide range of heating and cooling applications ofthe nature referred to in the Field. It is a very economically producedand potentially low-priced unit, in general performing the functions ofthe structure of the first identified McGuffey patent.

The arrangement of the interrupted and staggered weld zones, preferablyin a generally serpentine arrangement for a reversing parallel flow ofthe fluid transfer medium from inlet to outlet, plus the improvedfeature of stamped plate and nipple fitting subassemblies, affords ampleand sufficient ingress and egress volume to efficiently and balancedlyservice the interior of the exchanger unit with no local entrapment ofthe heat transfer medium, whether liquid or vaporous. The welds, assymmetrically arranged in a fixed parallel zonal relationship, enable anaccurately predictable hydraulic pressure expansion of the unit inmanufacture, without resort to the expedient of tensioning the componentsheet metal plates during welding, as in the case of the prior artMueller patent identified above.

It has been found that the improved unit effectively outperformscorrespondingly simple heat transfer units of even generally similardesign and manufacturing characteristics.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevational view,partially broken, of a typical plate heat exchange unit in one of a fewbasic styles contemplated by the invention;

FIG. 2 is an enlarged scale fragmentary view in side elevation bettershowing the weldments which unite the fitting pad component to thewelded plate component of the unit;

FIGS. 3 and 4 are similarly enlarged scale fragmentary views in verticalsection along lines 33 and 4--4, respectively, of FIG. 1, FIG. 3indicating in dot-dash line the sectional outline of a fitting pad priorto its expansion to the finished sectional configuration shown in solidline;

FIG. 5 is a similar view in horizontal section on line 5-5 of FIG. 1;and

FIG. 6 is a fragmentary elevational view of the welded plate assemblyprior to application of the inlet and outlet fitting sub-assemblies andhydraulic pressure expansion of the unit.

DESCRIPTION OF A PREFERRED EMBODIMENT The improved unit, as generallydesignated by the reference numeral 10, essentially comprises a pair ofidentical weld-united sheet steel plates constituting an internallypassaged fluid flow distributing panel or plate sub-assembly, generallydesignated 11, of unit 10, being equipped with a pair of intake andoutlet fitting members or sub-assemblies 12, 13, respectively.

FIG. 1 shows a typical style in which these intake and outlet devicesare disposed on a common longitudinal margin of plate component 11,adjacent an upper corner thereof. In other styles, depending upon spacelimitations or other practical considerations in use, said fittingsmight be applied in vertically spaced relation to one another at anextreme upright side margin of the plate structure, or otherwise.Handling grip elements 14 welded to the plate structure 11 are ofsecondary significance.

In the production of the transfer unit 10, a pair of like opposite siderectangular plates 16, 17 are, in a perfectly flat condition of each,disposed in registered side-by-side and face-to-face contact with oneanother and, as thus held tightly in an appropriate clamping fixture,subjected to welding thereof in this unitary condition, employingequipment and a mechanical procedure such as are the subject matter ofthe copending application, Ser. No. 346,294 referred to above.

This is done prior to the application of the pad-type fittings 12, 13,and the weldments comprise continuous marginal seam welds 18, 19 aboutthe respective pairs of horizontal and vertical sides of the assembledplates, being located well inwardly of the edges thereof, as indicatedin FIGS. 2, 4 and 5. As appears in FIGS. 1 and 6, another upright seamweld 20 is made paralleling and in laterally inwardly spaced relation tothe upright left-hand marginal seam weld 19, thus defining a verticalzone in which an upright fluid discharge header passage will be isolatedfrom horizontal flow distribution passages, both later described, exceptthe bottom one.

For the rest, plates 16 and 17 are continuously seam welded along linesparallel to and vertically spaced from one another; and in the typicalillustrated unit the pattern of these continuous welds will include aninternal seam weld 21 which commences from the left at upright weldmentand continues to the right a major portion of the horizontal length ofthe unit 10, but terminating well short of the right-hand verticalmargin weld 19. This seam union 21 is spaced vertically from a secondhorizontal seam 22 of substantially the same length, but extending tothe left from the righthand upright seam 19 a distance generallycorresponding to the length of seam 21, i.e., terminating well short ofheader weld 20; and a third horizontal seam weld 23 duplicates inrelative position and extent the continuous weldment 2] commencing fromthe bottom of seam weld 20. However, the vertical spacing of weld 23above bottom margin weld l8 somewhat exceeds the spacing of the threehorizontal seams 21, 22, 23 from one another; the purpose being tooutline an augmented initial horizontal flow distribution zone, as willappear.

At the time of making such parallel seam welds the plates 16, 17 arealso intermediately welded and interiorly sub-divided in part intoelongated horizontal pass areas generally separated from one another byseams 21, 22 and 23. This subdivision is afforded by a plurality ofseries of interrupted seam or spot-like welds individually designated25, which are produced in a single welding cycle by the improvedequipment referred to above. Thus, there will typically be, in alongitudinal horizontal area between continuous weld 21 and the seamweld 18, two parallel rows of said interrupted weldments 25 whichgenerally define three distributional flow pass zones directlysucceeding one another downwardly.

The patterning is such that the two rows of welds 25 above seam weld 21are longitudinally and transversely staggered relative to one another. Asimilar pattern characterizes the zone between the pairs of seam welds21, 22 and 22, 23, and by preference (as indicated above) the horizontaldistribution area between continuous weld 23 and the bottom marginalweld 18 is sufficiently wider than the three above zones to accommodatefour rows of the interrupted and staggered welds 25. The result is that,in each of these seam weldsubdivided zones there is a distinctpatterning between continuous and interrupted weldments in a symmetricaldiamond shape, as suggested at several places in dot-dash line in FIG.1.

In practice, the lines of welding, continuous and interrupted, aremachine-commenced at a central zone, being progressively outwardlyproduced in order to obtain an ironing effect maintaining true smoothflat-wise contact of the sheets l6, 17 as they are being welded andafter welding.

Thus united in a two-ply, flat plate structure, the sheet or platesub-assembly 1 1 is marginally cut as indicated in FIG. 6, to providethe respective larger and somewhat smaller rectangular edge notches 27,28 at which the respective fitting pad units 12, 13 are to be applied,although the notching may, of course, be done prior to welding.

The structural composition of fitting sub-assemblies 12, 13 is the samesave for size, being best depicted in FIGS. 2 and 3. It comprises anelongated tubular, nipple-like pipe length 29, threaded at an outer endfor attachment in the circulating line of the heat transfer medium; andthis fitting part is surrounded at its lower end by semi-cylindricalformations 30 (FIG. 3) of a pair of identical sheet metal stampings 31.These, as prepared for application to the fitting length 29 and tosubunit 1 1, have a downwardly tapered sectional configuration adjoiningcylindrical portions 30 to their extremities 32 remote from the latter,at which said extremities the stampings 31 are sufficiently spacedlaterally from and generally parallel to one another to fit slidablyover the respective notches 27, 28 of plate sub-assembly 11, fullystraddling across said notches as appears in FIG. 2.

But preferably prior to this assembling of the fitting component 12 or13 to the plate sub-assembly 11 it is united as an integral combinationof stamped plates and pipe 29 by seam-welding its semi-cylindrical plateformations to said fitting part 29 about the circumference of thelatter, as at 33, and by further seam-welding the outer stamped platemargins to one another, as along an outer seam 34 paralleling themarginal plate seaming at 18.

The thus sub-assembled units 12, 13 are then straddled over the notchedplate zones 27, 28 to span the latter and their welded final securementto the exterior plate surfaces of sub-assembly 11 is completed along theU-shaped seam contours 35.

Completion of the product 10 now requires only that the plate structurebe placed in an appropriate fixture and physically expanded by theapplication of hydraulic pressure of, say, 750 psi. to blow up itsinterior under the closely predictable control of the internal seam andspot welding pattern to produce pillow-like fluid distribution spaces ofthe sectional outline shown in FIGS. 4 and 5. The diamond outlinethereof, as distinguished from a rectangular box-like outlinecharacteristic of the product of the Mueller patent, affords full anddirect unimpeded intercommunication of these spaces with one anotheralong both diagonal and related distribution paths, and throughout thelength and breadth of the interrupted weld passes, yet with a verystrong and unimpaired internal union of plates 16, 17 with one another,attributable to the staggered-row patterning.

The size of the inlet fitting header cross section or space 38 (FIG. 3)assures an ample, unthrottled admission of heating medium to the plateinterior, free of any degree of trapping that fluid in this entry zone;and the proportioning of the other or outlet fitting 13, as communicatedwith the expanded discharge header 39 (FIG. 5) defined between theparallel upright seam welds 19 and 20, similarly accommodates anunrestricted exhausting of the transfer fluid to its circulation line.

As previously noted, the exchanger 10 is capable of inexpensivemanufacture in a limited number of models, differing in size andinternal capacity, specific location of inlet and outlet fittings,number of serpentine passes, etc., to satisfy many performancespecifications. Indeed, there may be instances of which continuousinternal seam welding, to define the illustrated serpentine zones orpasses, i.e., other than about the margins of the unit, is dispensedwith, internal or intermediate welding being solely through the agencyof the low gitudinally interrupted, staggered row spot-like welds 25 inthe above-described pattern of distribution.

What is claimed is:

l. A method of making a plate-type heat exchange unit, comprisingassembling a pair of similar flat plate components in flat-wise,face-to-face contact with one another, with said components formed toafford marginal notching extending therein from an edge and in the planethereof, marginally and intermediately securing said assembledcomponents unitarily to one another by a welding pattern includingsuccessive spot-like welds, preparing at least one rigid fluid flowfitting unit including a cylindrical fitting and a pair of like stampedplate members shaped and rigidly secured to said fitting incircumferentially surrounding relation to a portion of the latter, withthe remainder of said plate members being in the main in fixed flat-wisespacing relative to one another to straddle said marginal componentnotching, thus straddling the fitting unit and rigidly securing saidremainder thereof to sides of the assembled plate components, and usingsaid cylindrical fitting and plate members in internally expanding theinterior of the unitarily welded component assembled under externalfluid pressure applied at said marginal notching and between said platecomponents, thus to afford spaces of pillow-like sectional contourbetween the plate components, adjacent ones of such spaces being indirect open communication, longitudinally and later ally, with oneanother.

2. A method of making a plate-type heat exchange unit, comprisingassembling a pair of similar flat plate components in flat-wise,face-to-face contact with one another, with said components formed toafford marginal notching extending therein from an edge and in the planethereof, marginally and intermediately securing said assembledcomponents unitarily to one another by a welding pattern includingsuccessive parallel rows of interrupted, spot-like welds which are insuccessive rows in longitudinally and laterally staggered relation toone another, and further relatively continuous, seam-like weldsseparating certain of said rows from other thereof, preparing at leastone rigid fluid flow fitting unit including a cylindrical fitting and apair of like stamped plate members shaped and rigidly secured to saidfitting in circumferentially surrounding relation to a portion of thelatter, with the remainder of said plate members being in the main infixed flat-wise spacing relative to one another to straddle saidmarginal component notching, thus straddling the fitting unit andrigidly securing said remainder thereof to sides of the assembled platecomponents, and using said cylindrical fitting and plate members ininternally expanding the interior of the unitarily welded componentassembly under external fluid pressure applied at said marginal notchingand between said plate components, thus to afford diamond-shaped spacesof pillow-like sectional contour between the plate components, adjacentones of such spaces being in direct open communication, longitudinally,laterally, and diagonal-wise, with one

1. A method of making a plate-type heat exchange unit, comprisingassembling a pair of similar flat plate components in flat-wisE,face-to-face contact with one another, with said components formed toafford marginal notching extending therein from an edge and in the planethereof, marginally and intermediately securing said assembledcomponents unitarily to one another by a welding pattern includingsuccessive spot-like welds, preparing at least one rigid fluid flowfitting unit including a cylindrical fitting and a pair of like stampedplate members shaped and rigidly secured to said fitting incircumferentially surrounding relation to a portion of the latter, withthe remainder of said plate members being in the main in fixed flat-wisespacing relative to one another to straddle said marginal componentnotching, thus straddling the fitting unit and rigidly securing saidremainder thereof to sides of the assembled plate components, and usingsaid cylindrical fitting and plate members in internally expanding theinterior of the unitarily welded component assembled under externalfluid pressure applied at said marginal notching and between said platecomponents, thus to afford spaces of pillow-like sectional contourbetween the plate components, adjacent ones of such spaces being indirect open communication, longitudinally and laterally, with oneanother.
 2. A method of making a plate-type heat exchange unit,comprising assembling a pair of similar flat plate components inflat-wise, face-to-face contact with one another, with said componentsformed to afford marginal notching extending therein from an edge and inthe plane thereof, marginally and intermediately securing said assembledcomponents unitarily to one another by a welding pattern includingsuccessive parallel rows of interrupted, spot-like welds which are insuccessive rows in longitudinally and laterally staggered relation toone another, and further relatively continuous, seam-like weldsseparating certain of said rows from other thereof, preparing at leastone rigid fluid flow fitting unit including a cylindrical fitting and apair of like stamped plate members shaped and rigidly secured to saidfitting in circumferentially surrounding relation to a portion of thelatter, with the remainder of said plate members being in the main infixed flat-wise spacing relative to one another to straddle saidmarginal component notching, thus straddling the fitting unit andrigidly securing said remainder thereof to sides of the assembled platecomponents, and using said cylindrical fitting and plate members ininternally expanding the interior of the unitarily welded componentassembly under external fluid pressure applied at said marginal notchingand between said plate components, thus to afford diamond-shaped spacesof pillow-like sectional contour between the plate components, adjacentones of such spaces being in direct open communication, longitudinally,laterally, and diagonal-wise, with one another.